Cees Otto

Due to health concerns, the European Union has banned the use of titanium dioxide nanoparticles in consumables in February 2022, with a 6-month transitional period ending in August 2022. We studied the prevalence of titanium dioxide nanoparticles in synovial fluid samples during and after the transitional period. A total of 302 samples were collected as a consecutive series between 1 April 2022 and 15 June 2023 from patients visiting the department of rheumatology at VieCuri Medical Centre in Venlo, The Netherlands. The samples were primarily collected for diagnostic purposes and only clinical waste material was used for this study. From each sample, up to 40 μl of fluid was analysed with Raman spectroscopy for the presence of titanium dioxide particles. The trend in prevalence was calculated with a 3-month wide moving average. A total of 13 out of 302 samples (4.3%) contained titanium dioxide (TiO2). The prevalence of TiO2 decreased between the transitional period and the period after the ban (p = 0.0154, with a relative risk ratio of 4.9 (95% CI 1.35–17.74). There was no significant difference in patient characteristics between the TiO2 positive and the TiO2 negative group. These results are hinting towards a possible relationship between the EU-ban and the identified decrease in prevalence.